The subject matter disclosed herein relates to variable frequency drives (VFDs), and more specifically to VFDs for driving electric machines used with electric submersible pumps (ESPs) in oil and gas applications.
In typical oil and gas drilling applications a well bore is drilled to reach a reservoir. The well bore may include multiple changes in direction and may have sections that are vertical, slanted, or horizontal. A well bore casing is inserted into the well bore to provide structure and support for the well bore. The oil, gas, or other fluid deposit is then pumped out of the reservoir, through the well bore casing, and to the surface, where it is collected. One way to pump the fluid from the reservoir to the surface is with an electrical submersible pump (ESP), which is driven by an electric motor (e.g., an induction motor or a permanent magnet motor) in the well bore casing. Unscheduled downtime of the ESP or electric motor may incur costs for diagnosis of the downtime, replacement of components, maintenance, deferred production, or any combination thereof.